Prognostic Significance of Standardized Uptake Value on (18)Fluorine-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Patients with Nasopharyngeal Carcinoma

The aim of this study was to investigate the prognostic significance of standardized uptake value (SUV) on 18 fluorine-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with nasopharyngeal carcinoma (NPC). Thirty-four patients who have histologically proven NPC and underwent (18)F-FDG PET/CT were included in this study. After (18)F-FDG PET/CT, all the patients received radiation therapy and 32 of them received concomitant weekly chemotherapy. The maximum SUV (SUV(max)) at the primary tumor and the SUV(max)of the highest neck nodes were determined. The SUV(max)-T ranged from 5.00 to 30.80 (mean: 15.37 ± 6.10) and there was no difference between SUV(max)-T values for early and late stages (P = 0.99). The SUV(max)-N ranged from 3.10 to 23.80 (mean: 13.23 ± 5.76). There was no correlation between SUV(max)-T and SUV(max)-N (r = 0.111, P = 0.532). There was no difference between the SUV(max)-T and the positivity of neck lymph nodes (P = 0.169). The ability of SUV(maks)-N to predict stage was obtained by a receiver operating characteristic (ROC) analysis. The area under the curve is 0.856 and the best cut-off value is 7.88. There was a good correlation between SUV(max)-N and stage. While the mean SUV(max)-T for the alive patients was slightly lower than that for the dead (14.65 ± 5.58 vs. 20.30 ± 7.92, P = 0.061), the difference between the groups was not statistically significant. Furthermore, there was no statistically significant difference for SUV(max)-N between these two groups (P: 0.494). Cox-regression analysis showed that an increase in SUV(max)-T and SUV(max)-N was associated with death risk (relative risk [RR]: 1.13, P = 0.078 and RR: 1.052, P = 0.456, respectively). SUV(max)-T and SUV(max)-N were independent prognostic factors for survival in NPC patients. This will help the clinicians in choosing suitable candidates for more aggressive treatment modalities.